There are many procedures and systems for treating vascular or venous obstructions that are occluded with atheroma, plaque, calcific material, and the like. Such obstructions are often referred to as vascular chronic total occlusions. Total occlusions can be treated, for example, by a surgical bypass procedure or a catheter-based intervention such as angioplasty.
Catheter-based intervention procedures may require the positioning of a guidewire through the occlusion. However, hard occlusive material can be difficult or almost impossible to penetrate. Often, during such procedures, the guidewire deflects from the occlusion and penetrates into an extraluminal space (i.e., subintimal or outside the vessel). The guidewire may even perforate the vessel, resulting in the distal end of the guidewire positioned outside of the vessel wall. Such perforations are very dangerous in certain circulations (e.g., in the brain and the heart). But, perforations are less risky in peripheral arterial circulations and in most of the venous system due to the muscular tissue surrounding these areas. A guidewire positioned in the extraluminal space, between layers of the vessel or outside of the vessel, must be repositioned and/or directed into the central lumen of the vessel. However, redirecting the guidewire is often difficult or impossible, even with the use of ancillary deflecting catheters or devices.